Synthetic studies with podocarpic acid

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dc.contributor.advisor Professor R.C.Cambie en
dc.contributor.advisor Brian Palmer en
dc.contributor.advisor Dr. Roger Read en Robertson, John David en 2007-11-13T01:13:43Z en 2007-11-13T01:13:43Z en 1980 en
dc.identifier.citation Thesis (PhD--Chemistry)--University of Auckland, 1980. en
dc.identifier.uri en
dc.description.abstract A series of reactions of podocarpic acid has been investigated. These include the preparation and ozonolysis of some podocarpa-8,11,13-6β,19-olides, the diborane-boron trifluoride reduction of the 7-keto and the 6β,19-lactone groups of 12-methoxy-7-oxypodocarpa-8,11,13-trien-6β,19-olide (21), and the addition of bromine azide to some 12-methoxypodocarpa-6,8,11,13-tetraene derivatives which gave products of unexpected stereochemistry. Ozonolysis of podocarpic acid gave the 8α,12-lactone of 8β-hydroperoxy-(13-17)-pentanorlabdan-19-oic acid (82) which was reduced to the hydroxy-lactone (83) and the keto-diacid (84). The esters (81) and (87) of compounds (83) and (84) were prepared and used as model compounds for the attempted synthesis of the fungicide LL-21271α. An efficient method for generating an exocyclic methylene group at C-8 of the (13-17)-pentanorlabdane skeleton was found, and the preparation and some reactions of the epoxides of dimethyl (13-17)-pentanorlabd-8(17)-en-12,19-dioate (130) and dimethyl (13-17)-pentanorlabd-8(9)-en-12,19-dioate (133) have been investigated. Bromination of 8-oxo-(13-17)-pentanorlabdan-dioic acid esters gave unexpected 7α-bromo derivatives. Methyl, hydrogen 7α-bromo-8-oxo-(13-l7)-pentanorlabdan-12,l9-dioate (162) was found to undergo an unusual elimination and decarboxylation reaction to give the methylene ketone (166) which underwent dimerisation affording compound (167). Some C-19 oxygenated compounds that were expected to have ambergris-type odours were prepared and found to be odourless. An improved method of reduction of methyl-12-methoxy-7-oxopodocarpa-5,8,11,13-tetraen-19oate (199) to 12-methoxypodocarpa-5,8,11,13-tetraen-19-ol (201) was found and the mechanism was studied. A series of C-19 methyl ethers of podocarpic acid derivatives was prepared in order to elucidate the above reduction mechanism. Also investigated were the functionalisation of the C-10 axial methyl group of podocarpic acid via photolysis of the 6β-nitrite ester for the preparation of 12-methoxy-19-norpodocarpa-3,5,8,11,13-tetraen-7-one (237), and the photo-oxygenation of 12-methoxy podocarpa-6,8,11,13-tetraen-19-oic acid (57) to give a 4-hydroperoxide (240) which was subsequently reduced to 12-methoxy podocarpa-4,8,11,13-tetraen-7-one (243). en
dc.format Scanned from print thesis en
dc.language.iso en en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA218761 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights.uri en
dc.title Synthetic studies with podocarpic acid en
dc.type Thesis en Organic Chemistry en The University of Auckland en Doctoral en PhD en
dc.subject.marsden Fields of Research::250000 Chemical Sciences::250300 Organic Chemistry en
dc.rights.holder Copyright: The author en
pubs.local.anzsrc 03 - Chemical Sciences en Faculty of Science en
dc.identifier.wikidata Q112848307

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